Proximity monitoring communication system

• US 6,563,427 B2
• Filed: 09/28/2001
• Issued: 05/13/2003
• Est. Priority Date: 09/28/2001
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Bero, Robert J., Alberth, William P. Jr.
• Primary Examiner(s): Wu, Daniel J.
• Assistant Examiner(s): NGUYEN, HUNG T
• Application Number:
  US09/967,239
• Publication Number:
  US 20030063003A1
• Time in Patent Office: 592 Days
• Field of Search: 340/573.1, 340/573.4, 340/539, 340/568.1, 340/825.24
• US Class Current: 340/573.1
• CPC Class Codes: G08B 21/0225 Monitoring making use of different thresholds, e.g. for different alarm levels
• CPC Class Codes: G08B 21/0227 System arrangements with a plurality of child units
• CPC Class Codes: G08B 21/023 Power management, e.g. system sleep and wake up provisions
• CPC Class Codes: G08B 21/0247 System arrangements wherein the alarm criteria uses signal strength

Abstract

A method of personal location monitoring in a wireless communication system operating on a local area network. The method includes initializing a master communication device and a slave monitor device on the local area network. A next step transmitting a signal on the local area network by the slave monitor device. A next step includes the communication device receiving the signal on the local area network and measuring the signal strength which is compared to a threshold. A next step includes triggering an alarm in the communication device when the signal strength falls below the threshold, indicating that the monitor device is straying from the proximity of the local area network.

Claims

1. A method of proximity monitoring in a wireless communication system operable on at least two wireless local area networks, the method comprising the steps of:

providing at least two wireless master communication devices supporting respective wireless local area networks and at least one wireless monitor device as a slave unit operable in the wireless local area networks;

transceiving signals between the at least one monitor device and at least one of the master communication devices on the respective wireless local area network;

triggering an alarm in at least one of the master wireless communication devices when there is an indication that the at least one wireless monitor device is no longer within the proximity of either of the wireless local area networks; and

transferring the monitoring of the at least one monitor device from a first wireless master communication device to a second wireless master communication device of the at least two wireless master communication devices, comprising the substeps of;

communicating between the first and second wireless communication device on a wide area network for transferring the at least one monitor device therebetween,

providing a time-out period for the at least one monitor device to transfer from the local area network of the first communication device to the local area network of the second communication device

acknowledging the receipt of the at least one monitor device into the second local area network by the second communication device to the first communication device over the wide area network, and

wherein the triggering step includes triggering the alarm if the time-out period expires before the transferring step is complete.

2. The method of claim 1, wherein the transceiving step includes measuring the signal strength of one of the monitor devices at a predefined proximity boundary in the local area network by one of the at least two communication devices to define a threshold, and further comprising a step of assigning the threshold to all the monitor devices to define a group threshold, and wherein the triggering step includes triggering an alarm when the signal strength from any of the monitoring devices falls below the threshold.

3. The method of claim 1, wherein the transceiving step includes measuring the signal strength of each of the at least one wireless monitor devices at a proximity boundary predefined for each monitor device in the local area network to define individual thresholds therefor, and wherein the triggering step includes triggering the alarm when the when the signal strength from any of the monitoring devices falls below their respective individual threshold.

4. The method of claim 1, wherein the transferring step further comprises the substep of transmitting the time-out period to the second communication device, and wherein the triggering step includes triggering of the alarm in the second communication device if the timeout period expires before the second communication device receives the signal from the at least one monitoring device.

5. The method of claim 1, further comprising the step of slaving each of the at least one wireless monitor devices to an authorized master communication device with the strongest received signal when the local area networks are merged.

6. The method of claim 1, wherein the providing step includes the at least one wireless communication devices being operable on a wide area network, wherein after the comparing step further comprising the steps of:

if the signal strength from the slave unit to the master unit is no longer detected, querying at least one other of the at least one communication devices on the wide are network to determine if any of these communication devices can detect the particular slave unit in question on their associated local area network;

waiting a timeout period for all such at least one other communication devices to respond affirmatively; and

transferring master authority over the slave unit to any of the at least one other communication devices that responds affirmatively during the waiting step.

7. A proximity monitoring communication system using at least two wireless local area networks, the system comprising:

at least two master wireless communication devices operable on a wide area network with each master wireless communication device supporting a respective wireless local area network; and

at least one wireless monitor device operable as a slave unit in an associated wireless local area network, the at least one wireless monitor device transceiving signals on the local area network with a first of the at least two master wireless communication devices;

the at least two master wireless communication devices operable to detect a received signal from the at least one wireless monitor device, wherein loss of detection of the received signal in a particular local area network triggers an alarm on the wireless communication devices supporting the particular local area network, indicating that the at least one wireless monitor device is no longer within the proximity of the particular local area network, and wherein;

the first master communication device communicates to a second master communication device on the wide area network that the at least one monitor device will be transferred from the local area network of the first communication device to the local area network of the second communication device, and wherein the first communication device provides a timeout period for the at least one monitor device to transfer to the local area network of the second communication device, and the receipt of the at least one monitor device into the local area network of the second communication device is acknowledged by the second communication device to the first communication device over the wide area network, and the alarm is triggered if the time-out period expires before the transfer is complete.

8. The system of claim 7 wherein the wireless communication devices are operable to measure a strength of the received signal from the at least one wireless monitor device at a predefined proximity boundary in the local area network to define a threshold that is applied to all the monitor devices to define a group threshold, wherein a received signal strength of less than the threshold from any of the monitoring devices triggers the alarm.

9. The system of claim 7, wherein the signal strength of each of the at least one wireless monitor devices is measured at a proximity boundary predefined for each monitor device in the local area network to define individual thresholds therefor, wherein when the signal strength from any of the monitoring devices falls below their respective individual threshold the alarm will be triggered in at least one of the at least two wireless communication devices.

10. The system of claim 7, wherein the time-out period is communicated to the second communication device to trigger the alarm therein if the timeout period expires before the second communication device receives the signal from the at least one monitoring device.

11. The system of claim 7, wherein each of the at least one wireless monitor devices will slave to an authorized master communication device with the strongest received signal when the local area networks are merged.

12. The system of claim 7, wherein if the signal from the slave unit to the first master communication device is no longer detected, the first communication device queries the second master communication device on the wide are network to determine if the second master communication device can detect the particular slave unit in question on its associated local area network, wherein the first master communication device waits a timeout period for the second communication device to respond affirmatively and transfers master authority over the slave unit to the second communication device upon such affirmation.